Process of preparing sex hormones



Patented Mar. 26, 1946 I i Y 7 PROCESS OF PR1:PARING: SEX HORMONESRussell Earl Marker, State College, Pa., and Eugene L. Wittle, Detroit,Mich., assignors to Parke, Davis & Company, Detroit, Mich a'cor-.poration of Michigan No Drawing.

Original application October 25,

1940, Serial No; 362,836. Divided and this application December 2, 1943,SerialNo. 512,602

, ficlaims.

This invention relates to a process of Preparing sex hormones, and moreparticularly, to a new and improved process for the. preparation ofsteroidal hormones from sterols and bile acids.

This application is a division of our copending application, Serial No.362,836, filed October 25, 1940.

One object .of this invention is to afford a process whereby compoundssimply convertible into sex hormones can be prepared from sterols orbile "1o pentachloride or thionyl chloride to form cholesacids inimproved yields.

Another object of this invention is to aflford a simplified process forthe preparation of compounds simply convertible into sex hormones.

Yet another object of this invention is to afford anew process for thepreparation of A -3-keto steroids such as the sex hormones from A-nsaturated steroids. ,Y

-- Other objects will become apparent on perusal of this specificationand the appended claims.

We have developed a process in which the oxidation proceeds in goodyields togive intermediates which can be converted simply and in goodyields to the sex hormones.

Our process consists essentially in treating a steroid 01' the formula,

where R is a member of the group consisting of hydrocarbon radicals andoxygenated hydrocarbon radicals, X is a halogen, and one of Y and Z tionproducts having a shortened side-chain thus obtained to obtain thecorresponding A -unsaturated steroids. and treating these with an agentcapable of oxidizing a methylene group adjacent to a double bond thusforming the corresponding 3-keto A -unsaturated steroids having ashortened side-chain.

In greater detail, our new process consists first in forming a A- orAF-unsaturated sterol or bile acid derivative. Because of theiravailability, we

prefer to use as starting materials, the naturally ll occurring sterolsinwhich the side-chain R is a I hydrocarbon radical containing 8 to 10carbon This side-chain may be saturated, as in atoms. cholesterol CaHuor sitosterol CmHai. or it may be unsaturated as in ergosterol CoHrv:Sterols of this type are readily converted into the corresponding3-desoxy compounds, i. e. into the A or A unsaturated hydrocarbons. Thuscholesterol may be distilled at atmospheric pressure to give Acholestene, or it may be treated with phosphorous teryl chloride, andthe latter reduced as for example with sodium and amyl alcohol to yieldA cholestene. m

The A or A -unsaturated steroidal hydrocarbon used as a startingmaterial is first treated with halogen or hydrohalic acid to add. theelements of these substances to the steroidal double bond. We prefer touse chlorine, bromine, hydrogen chloride 'or hydrogen bromide in thisstep. The compound thus obtained has a halogen atom attached to C5 andanother halogen atom or hydrogen atom, depending upon whether halogen orhydmhalic acid was added, is attached to the other carbon atom of theoriginal double bond.

The dihalide or hydrohalide addition product thus obtained is thenoxidized under condition: suiiiciently vigorous to rupturecarbon-to-carbon bonds. While a variety 01' agents maybe employed forthis purpose, we prefer to use chromic acid, ermanganic acid or'theirsalts and we find it most convenient to conduct the oiddation in aceticacid below C. and preferably at 35-60 After the oxidation has b'eencompleted, the products are separated so as to recover any startingmaterial and then the oxidation product consisting oi a mixture ofsteroids having shortened, oxygenated side-chain is separated into itscomponents according to several possible methods. It is convenient toremove the elements of halogen or hydrohalic acid at this point bytreatment with a dehalogenating or dehydrohalogenating agent. Suitabledehalogenating agents include sodium iodide, zinc and acetic acid,metallic magnesium, and the like, and suitable dehydrohalogenatin agentsare basic substances such as pyridine, sodium acetate and other alkalimetal salts of carboxylic acidsQand the like.

If a M-unsaturated steroid ha been used as a starting material or ifhydrogen halide was the agent added to the unsaturated steroid (either Aor A then the product formed after removal of the elements of halogen orhydrohalic acid, as the case may be. is a M-unsaturated compound;

If, however, the dihalide of a A -unsaturated steroid was the substanceoxidized. after removal of the elements of halogen the product obtainedis a A -unsaturatcd steroid and it is necessary at some point in theprocess to convert this into a a' -unsaturated, steroid. This is done byadding and then removing the elements of hydrohalic acid. I

This shifting of the double bond from A to A in the oxidation productsmay be carried out at any stage after the unreacted starting materialhas been removed from the oxidation products but it must, of course, bedone before the steroid is again oxidized to form the 3-keto steroid asset forth later in the specification.

The mixture of oxidation products is conveniently worked up by firstseparating the acidic and the non-acidic fractions according to methodswell known in the art. The non-acidic fraction thus obtained is furthertreated to isolate the ketonic fraction and from the ketonic fractionthe 17 -keto-androstane compound and the '20-keto-pregnane compound areisolated. Then the l'l-keto-androstane compound, if it still has thedouble bond in the A -position, may be converted into the correspondingM-androstenone-l'l.

The M-androstenone-l'l thus obtained may be oxidized according to ournew method to form M-androstendione-iid'l. andthe latter selectivelyreduced to form A -androstenol-1'7-one-3 (testosterone). Otherwise the A-androstenone-17 may first be selectively reduced under conditions whichleave a double bond unaltered so as to form A- androstenol-l7, thehydroxyl group of the latter protected by conversion into a derivativehydrolyzable to regenerate. A -androstenol-1'I and this derivativeoxidized according to our new method to form the correspondingderivative of A -androsten0l-17-one-3.

In either case the process involves the use of our new method for thepreparation of A -un-- saturated 3-keto steroids from A -unsaturatedsteroids. This method consists in oxidizing to a ketone group. amethylene group adjacent to a double bond and this oxidation isefl'ected by first protecting any hydroxylgroups by converting theseinto derivatives such as acetates, benzoates. trityl others or othergroups hydrolyzable to give OH and oxidizing the derivatives thusobtained with an agent capable of converting into a ketone group amethylene group adjacent to a double bond. Such agents include chromicacid and perm'anganic acid and their salts, as well as selenium dioxide.The conditions of reaction depend on the particular oxidizing agentemployed, e. g. we prefer to use chromic acid in acetic acid at 30- 60C.

The selective reduction of M-androstenone-l'? may be accomplished with awide variety of reducing agents. These include catalytic hydrogenationwith a Raney nickel catalyst, and the combination of an alkali oralkaline earth metal or aluminum and a substance having reactivehydrogen atoms. Reducing agents of the latter class include suchcombination as sodium and ethyl alcohol. aluminum amalgam and aqueousammonium chloride, calcium and methanol, and the like. Instead of thesethe reduction may be conducted according to themethodof Meerwein andPonndorfi using, for example, ammonium isopropylate and isopropylalcohol.

Our invention may be more fully illustrated by the following examples.

Example 1 (a) In a 12 liter flask is placed 230 g. of A"- cholestenedibromid prepared, e. g., according to Mauthner, Monatsh. 27, 421(1906), and 500 cc. 01 carbon tetrachloride. When solution is complete,8 liters of glacial acetic acid are added and the solution warmed to 45C. with stirring. To this stirred solution at 4850 C. is added dropwisea stirred solution of 320 g. of chromic anhydride in 350 cc. of waterand 800 cc. of acetic acid over a period of four or five hours. Thesolution is stirred at 50 C. for six hours longer and then cooled withcold water or ice to 30 C. Then ethyl alcohol (250 cc.) is added slowlyto this stirred solution over a period of about one-half hour to destroyany excess chromic anhydride. The acetic acid is then removed underreduced pressure until the volume of the solution ha been reduced aboutone-half. During theevaporation the temperature of the solution is keptat 40-45" C. The solution is cooled slightly and the unchanged dibromidefiltered ofi and dried. The

layer is separated and extracted with 2.5 liters of ether. The combinedethereal extracts are washed well with 2 liters of water, 3 liters ofwater containing 300 cc. of cone. hydrochloric acid, and then twice with1.5 liters of salt water, suihcient salt being added to cause rapidseparation of the layers. The ethereal solution then is evaporated todryness, the last ether being taken off cautiously to avoid undue heat.The residue contains the dibromides of A -androstenone-17, A-pregnenone-20, and A -cholenic acid.

Instead of using A -cholestene dibromide in the above step, A-cholestene dichloride, A -sitostene dibromide, A -sitostene dichloride,or other dihalides of A -unsaturated hydrocarbons derived from sterolsmay be used instead.

(2)) One liter of acetic acid and 5 g. of zinc dust is added to thisresidue and the solution stirred vigorously and heated to C. on thesteam bath. A further 45 g. of zinc dust is added to, this stirredsolution in small portions over a period of forty-five minutes. Then thesolution is filtered from the caked zinc and the latter washed wellwithacetic acid. The acetic acid filtrate is evaporated to dryness in vacuoon the steam bath and the residue dissolved in 2 liters of ether. Theethereal solution is washed twice with water and the acid fraction isextracted with 5% sodium hydroxide solution until all acids are removed.

' Example 2 600 cc. of water, cc. of sulfuric acid, and 2 l.

of acetic acid is added over a period of four hours. The mixture isstirred four hours more at 50 C. and then sulfur dioxide passedinto thesolution with cooling. The mixture is concentrated to one-third itsformer volume in vacuo. 700 g. of sodium acetate added, and the mixturemamas refluxed for two hours. It is diluted with water and wellextracted with ether. The ethereal layer is shaken with 10% sodiumhydroxide and the sparingly soluble sodium salt which forms is removedby filtration. The filtrate, consisting of an ethereal and an aqueousphase, is set aside for later treatment as described under (d) below.

The sparingly soluble sodium. salt is suspended in water, and thesuspension acidified strongly. This mixture is well extracted with etherand the latter washed and evaporated. The residue is crystallized fromslightly diluted acetic acid and thus yields n' -cholenic acid of M. P.160 C.

(d) The ethereal layer in the filtrate is separated and washed well withsodium hydroxide solution and water. After removing the ether on a steambath, the residue is heated with 200 cc. of acetone, some methanoladded, and the mixture chilled. The crude M-cholestene which separatesis collected and recrystallized. The combined mother liquors areevaporated to dryness, and the ketonic constituents removed in the knownmanner with Girards reagent T. The

crude ketone mixture is distilled slowly in a high vacuum and a fractioncollected at 70-110 C. This is fractionally crystallized from dilutemethanol and thus yieldsiA -androstenone-17 of M.

(e) The combined mother liquors from the above described crystallizationof n -androstenone-17 contains A -androstenone-17 and A pregnenone-Z'O,and are evaporated to dryness and dissolved in 50 cc. of acetic acid. Tothis solution, at 45 C. there is added a solution of 1.5 g. of chromicanhydride in 20 cc. of 90% acetic acid over a period of a half hour. Themixture is poured into water, extracted with ether, and the etherealextract washed with sodium hydroxide .solution and water. The etherealsolution is dried over magnesium sulfate, evaporated to a small volume,and rendered cloudy by the addition of ligroin. On standing, crystals ofA androstenedione-3,l7 separate. After recrystallization, this productmelts at 170. The mother liquor from the separation of theN-androstenedime-3,17 is made slightly turbid with ligroin and filteredthrough a column of alumina. The filtrate is evaporated and yields.after crystallization from dilute acetone, progesterone .01 M. P.

Example 3 (a) A -Pregnenone-20, M. P. 105 C. may be isolated from themother liquors of the preparation of A-androstenone-1'7 as in .Example2' (d) or it may be prepared from A -pregnenol-3-flone-20 by the stepsof treatment with phosphorus pentachloride to obtain A-3-chloro-pregnenone- 20, treating this with sodium and amyl alcohol toobtain A -pregnenol-20-a, and treating this, to obtain A -pregnenone-20in the same manner as described in Serial No. 362,836 for thepreparatiipn oi A -androstenone-17 from M-androsterol- (b) To a solutionof 2 g. or 'A -pregnenone- 20 in 30 cc. or acetic acid at C. is addedover a periodoi' an hour, a solution of 2 g.

of chromic anhydride in cc. of acetic acid.

Alter standing two hours, sulfur dioxide is passed into the solution todestroy the excess chomic anhydride, and then the mixture is evaporatedin vacuo.

water, and the ethereal extract evaporated. The residue is sublimed in ahigh vacuum and then crystallized from dilute acetone and thus givesanhydride, removing the excess chromic anhydride and removingprogesterone from the mixture.

2. Process for producing progesterone comprising treating A-pregenone-20 with an oxidizing agent of the class consisting of chromicacid, permanganic acid, the salts of said acids and selenium dioxidethereby introducing a keto group in position-3 and forming progesterone,and removing the progesterone.

3. Process for producing progesterone comprising treating A-p'regnenone-20 with chromic anhydride in acetic acid at a temperatureof 30-60 C., and removing progesterone.

4. Process for producing progesterone comprising treating a solutioncontaining M-androst'enone-17 and A -pregnenone-20, with an oxidizingagent of the class consisting of chromic acid, permanganic acid, thesalts of said acids and selenium dioxide thereby obtaining A-androstendione'- 6. Process for producing progesterone comprisingtreating a solution containing A -androstenone-17 and A -pregnenone-20with chromic anhydride in acetic acid at a temperature of 30-80 C.thereby obtaining A -androstendione-3J7 and A -pregnendione-3,20 andseparating M-pregnendime-3,20 therefrom.

RUSSELL EARL MARKER.

EUGENE L. WI'I'ILE.

The residual sirup is dissolved in ether, shaken out with 5% sodiumhydroxide and

